Small wrinkles on skin are not favorable for smooth skin and are very important as an index of skin aging.
As skin is often directly exposed to ultraviolet rays of sunlight, the skin receives more oxidation-stress based on environmental factors than other organs do. The surface of the cell membrane of skin cells (chrotoplast) or the cell membrane of skin-cells contains a large amount of unsaturated fatty acids, and UV-rays advance the oxidation of these fatty acids.
Ultraviolet rays occupy 6% of sunlight. UVB (290 nm–320 nm) especially produces active oxygen on skin like ionizing radiations do. It is said that the active oxygen produces free radicals, and then by mediation thereof produces peroxidized lipids. As a result, it is possible that the cells lead to dysfunction like oxygen deactivation, or cause necrosis of the cells. Such aging of skin-cells appears on the surface of skin (epidermis) and becomes one of the factors that causes small wrinkles (exogenous factor).
In addition, skin is apt to lose water because it is exposed to outside air. The water content of human skin is usually about 60%. When the water content becomes less than 40% upon drying of the skin, the skin loses tension and gloss to cause small wrinkles (endogenous factor).
As ways for preventing small wrinkles, preparations containing the following substances are proposed: peptides having masking activity, such as tri- or tetra-peptide (Japanese Patent Publication A 56-115707), penta-peptide (Japanese Patent Publication A 56-115708) or new peptides (Japanese Patent Publication A 57-2213, Japanese Patent Publication A 57-2214); blood circulation promoters, such as carpronium chloride (Japanese Patent Publication A 62-39512), organic germanium compounds (Japanese Patent Publication A 63-183507) or inorganic germanium compounds (Japanese Patent Publication A 01-207217); humidic reservation agents such as hyaluronic acid (Japanese Patent Publication A 03-63209), and humidic reservation co-agents such as hyaluronidase inhibitors (Japanese Patent Publication A 06-279255, Japanese Patent Publication A 09-241148, Japanese Patent Publication A 10-130162).
However, packs containing the above-mentioned active substances have not accomplished enough effect for the prevention or improvement of keratinization of skin or small wrinkles of skin.
On the other hand, U.S. Pat. No. 5,889,062 discloses use of a combination of ubiquinone 10 or its derivative and a plastoquinone or its derivative for the care of aged skin.
Further, it is reported that in cosmetics, ubiquinone 10 is useful for protection against skin-aging (Japanese Patent Publication A 58-180410).
However, there have not been developed sheet-like packs dissolving the above-mentioned two problems, namely inhibition of oxidation-stress on skin (exogenous factor) and the water supply to skin in which water content decreases (endogenous factor).